UMBILICAL VENOUS D-DIMER CONCENTRATIONS WITH AND WITHOUT LABOR

Objective: To determine if labor activates the fetal fibrinolytic syst em. Methods: A total of 59 umbilical venous blood samples were collect ing following vaginal delivery at term (n = 20), cesarean delivery fol lowing labor at term (n = 12), vaginal delivery before term (n = 18), and cesarean delivery without labor (n = 9). D-dimer concentrations, a sensitive marker of fibrinolysis, were measured by enzyme-linked immu nosorbent assay, and compared between groups by Kruskel-Wallis and Man n Whitney U tests, with significance defined as P < .05. Results: Ther e were no significant differences in median D-dimer concentrations bet ween newborns delivered vaginally or by cesarean after term labor or p reterm labor. There were significant differences in median umbilical v enous D-dimer concentrations in subjects delivered vaginally or by ces arean after term or preterm labor compared with term subjects without labor delivered by cesarean (427, 773, and 326 versus 87 ng/mL, P = .0 1). Conclusion: Elevation of umbilical plasma D-dimer concentrations i n laboring patients suggests activation of fetal fibrinolysis before d elivery. (Obstet Gynecol 1998;92:184-6. (C) 1998 by The American Colle ge of Obstetricians and Gynecologists.)